Abstract

Fringing coral reefs provide a unique opportunity to study shallow aquatic ecosystems. A fringing coral reef system located in close proximity to a developed region was considered in this study. In such an environment the rate of decay of dissolved organic matter is high and the penetration of higher energy ultraviolet-B extends a greater influence on species diversity, particularly upon shallow benthic communities. Results from a nine month subsurface ultraviolet-B exposure measurement campaign performed at a site located on the southern Queensland coast (Hervey Bay, 25oS) are presented in this research. For this, a novel dosimetric technique was utilised to measure long-term subsurface ultraviolet-B exposures. The resultant data set includes exposure measurements made during the significant La Niña event of late 2010 which resulted in unprecedented high sea surface temperatures and severe flooding across eastern Australia, impacting upon the lagoon regions of the Great Barrier Reef and Queensland's southern estuaries, including the study site. The influence of season, diurnal tidal variation, cloud cover and solar zenith angle were analysed over the campaign period. Mean minimum daylight water depth was found to be the most significant factor influencing subsurface ultraviolet-B.